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2 
IRRIGATION AND THE FLORA OF THE PLAINS. 77 
surface of the plains is sere and brown save some “ eighties ” or 
larger tracts that are fenced, and under cultivation. 
You have perhaps crossed a broad, deep canal of swiftly-flowing, 
muddy water, and now in passing these fields of grain you hear 
the laughing voices of little streams. They are hidden from view 
by the standing growth, and at proper distances from each other 
they go, singing on their way across the gently sloping fields, 
making glad the hearts of the ranchmen, with their sure promises 
of an abundant harvest. Now right in the midst of one of these 
“eighties” of wheat, you behold a solid-half-acre of—can it be? 
Yes, those are certainly the long strap-shaped leaves, and the dark 
cylindrical spikes of Typha latifolia! the veritable Cat-tail Flag ; 
and growing more densely and luxuriantly than you ever saw it 
before. 
It is difficult to harmonize, in your mind, this patch of marsh 
with its close surrounding of thrifty grain, and equally difficult is 
it to reconcile the whole field with what seems to shut it in on all 
sides i. e. a seeming boundless, lifeless waste of withered prairie 
grass. There are now, on these plains, many acres of Cat-tail 
Flag where five years ago, no seed of a marsh plant would have 
‘germinated, because all was then more like an African desert than 
an American swamp. The change came after the following man- 
ner. The large ditch was first made from some stream before it 
leaves the mountains, and led along the higher ground, whence its 
waters were conducted to these lands below, which now constitute 
fertile fields. After one or twe seasons of irrigation, all slight 
hollows came to be occupied by shallow ponds. Why the sur- 
plus waters do not sink away into the earth beneath, you must 
learn from the geologist. The fact is they do not. Even during 
fall and winter when the water is turned off from the ditches, the 
ponds remain the same, the water in them falling but slightly be- 
low the ordinary level. 
The gossamer-winged seeds of the Typha are borne upon the 
winds by the thousand, from the valleys of the rivers below, to - 
these uplands. Here they find all circumstances favorable to 
germination, and the plants grow and spread rapidly ; sedges and 
other marsh plants growing with them, and the whole comes in the 
course of a few years to bear a strong contrast to the almost des- 
ert tracts around. 
In the settled, and consequently irrigated, portions of country 
